One approach for waterproofing could be making sure that all screws and gaskets are tight. Also use sealant such as the sealant attached.

I would recommend the Icotek KT 12 bk: Cable Grommets, small - 41312-1 for camera installs:

The rubber grommet is recommended for indoor/outdoor use with a temperature range of -30 90 degrees. I like the fact that it ensures a high degree of protection [up to IP65] while also providing strain relief. I was impressed that it is UV--resistant while other similar products did not state if there was resistance to UV. The only downside I could see about this grommet is if you do not size the  cable diameter correctly it could have water leaking through if it were used for outdoor installs.

Gorilla Clear 100% Silicone Sealant Caulk, Waterproof and Mold & Mildew Resistant

$8.99 on Amazon.

100% waterproof, dries clear, and works on any surface. 

It is rated for indoor/outdoor use, and is mold and mildew resistant. 

Is completely clear, and won't yellow or crack. 

Has a horrible odor associated with it. 

Used while installing cabling through conduit to close off ends and seal connectors going into conduit.

I haven't given much thought to other products rather than tried-and-true RTV

Benefits

   1.   Experience with product has always been good; no deterioration with time.

   2.   With careful application, won't detract from surrounding surface aesthetics.

   3.   Readily available and easily applied.

Potential Drawback

   1.   Can't be painted as needed.

I use the GE outdoor silicone

I prefer the small tube as opposed to the large caulking gun type due to it being easier to apply in tight areas and easier to handle while working on a ladder. It is a bit more expensive per oz. when buying in smaller amounts, but worth it to me.

I usually use the clear because it is less noticeable, unless I'm putting a white camera on a white building, then I'll use white. I use it to seal all penetrations, camera and backbox.

I go back to sites years later to do maintenance and find that this product holds up pretty well.

Also it skins over pretty fast, so if rain is on the way, you're usually in pretty good shape.

One drawback is that it can't be painted.

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I also like the Locktite G02

I have a number of cameras installed in carwash bays and have found that the powerful cleaners and constant moisture in this kind of environment can break down the seal between the glass lens cover and the camera on turret and bullet style cameras. By carefully applying a small bead of this to the edge of glass lens cover greatly protects the camera from getting moisture inside of it in these harsh conditions. Dries crystal clear, shock, water and temperature resistant,

This glue sets in 30 minutes and fully dries in 24 hrs. so it's not good to do on site. Better to apply and let fully dry at the shop, then install. I don't know if it is UV resistant, but I only use it in wash bays where the cameras don't see direct sunlight.

Product description: "Superior quality, multi-purpose sealant. Offers long-lasting flexibilty and excellent adhesion. Provide a weatherproof, watertight seal. Resists cracking, crumbling and chalking. Interior/exterior use. 50 Year Durability Guarantee. Meets Federal Specification TT-S-001543A, Class A."

This caulking would work well adhering to siding and waterproofing the install. This is relatively cheap and is built to last. This product comes in clear or white but I don't believe it is paintable. 

For cameras with a cable whip with a male RJ45 connector, a cable gland like this one may be helpful to keep the network connection water proof. Down side is it is rather expensive for what it does, there are cheaper alternatives out there.

I recently installed a camera on a residential yard lamp pole for a friend.  The camera had a female whip and I connected it to outdoor-rated cat 5.  I taped the connection heavily with electrical tape just in case water made it inside the pole.  I know that the cabling should not have shared space with the electrical cabling, but that's how he wanted it.  It was no surprise when the camera fried because I assumed it had picked up EMF from the 110v power line.  When I pulled the termination apart, it was soaked and presumably was the reason for the failure.  This is a low-budget project, so here's my solution for round 2:

I bought this watertight Carlton junction box with a rubber seal for about 8 bucks.  I cut half -inch slots in the back and attached 4-inch hose clamps and then drilled holes in the face to mount the camera.  I will seal the (very small) openings and the camera base with silicone.  This is what the box looks like mounted to a pole in my basement:

I had also purchased an Ambest waterproof RJ45 connector to put inside the box, but it's too big to fit in the box without kinking the cables.

One of the integrators I use at work recommended FlexTape to seal the connection.  It doesn't feel like the right thing to do, but he claims they use it all of the time. Thoughts?

-Dennis

https://www.lowes.com/pd/Gorilla-100-Silicone-All-purpose-Sealant-10-oz-Clear-Silicone-Caulk/1000217733

As others have mentioned, I like Gorilla Sealant because it is affordable, readily available and works on most surfaces and is 100% weather proof. 

For the wiring connections you could use "Permatex Liquid Electrical Tape"  You can purchase online through Amazon for 4oz for $9.10

Pros:

Provides a flexible coating

Waterproof-prevents moisture and corrosion

Eliminates the need for electric tape or shrink tubing

UV resistant

Cons:

Requires a min. of two coats and you have to wait 10min. between coats

4 hour dry time before you can restore power

     This does a good job at sealing up cracs around outdoor cameras and has worked for me. 

Cable glands are a good option for weatherproofing exterior cameras where cables enter a backbox or camera housing. These cable glands are cheap, efficient and have good specifications:

 https://www.jaycar.com.au/3-6-5mm-dia-waterproof-cable-glands-pk-2/p/HP0720

Benefits of these cable glands: 1) cheap (US$1.80 each) 2) flexible (can be used for cat 5 & 6 cable diameters) 3) IP68 rating

Disadvantages:

1)Won’t work with cable whips or non-standard sized knockouts and 2 )a nuisance to install.

We use strictly 100% silicone sealer for sealing our cameras from the elements and critters. Many products on the market, all are good if 100% silicone.

I like using this silicone, it's cheap lightweight and can fit into tight areas

I don't believe it's fire rated at all

Geocel 2300 caulk, construction tripolymer sealant, 10.3 oz.

Available in clear, white and other colors.

Advantages: remains flexible - doesn't crack, UV resistant, mold resistant

Disadvantages: expensive $9.00 / tube

We lean toward the Lexel product that Brian discusses in the original post. I've actually applied it to a penetration and around a wall mount camera while it was raining and it worked very well.

These appear that they will work well if you have to join some network cables together:

Usually, we penetrate through a wall directly to a camera and have very little cable exposed, but I can see this coming in handy maybe in a crawlspace or under an eave or soffit of some sort that could be exposed to the weather. I'd still use a exterior rated gel-filled Cat6 in that case rather than what the pictures shows as that jacket would likely deteriorate over time even if the junction stays good.

I've been using outdoor clear and white silicon sealer for sealing holes during installation. I'm also trying some of the waterproof cable connectors as below.

Loctite all purpose caulk.

E6800 provides ultra-violet resistance for marine and outdoor applications. It is an excellent insulator against water, corrosion from salt spray, bacteria, most chemicals and vibration. E6800 maintains its adhesive strength, even when submerged under water

Tough one! All exterior cameras we use are outdoor rated and come with their own weatherproofing in the form of gaskets, grommets, whips with and without twist. So the issue is usually wall penetration and sealing cable and fasteners of all kinds. This is where caulking usually comes in. A quick search for harsh environment solutions found this:

 L-Com RJ45 Glands and Couplers

Prices vary but are well worth protecting a camera that is way more expensive. 

Lot of options here.  There is caulk, 3m super 77, gaskets, etc. I have used duck tape to temporary seal...and temporary solution so far has turned into permanent solution.  I have to go back and take care of it before next rain storm. 

Lexel is the duct tape of all caulks. Super-elastic. Superior adhesion. Paintable. It seals around anything: tubs and shower stall, sinks and counter tops, window frames and door frames, PVC and metal drain pipes. Apply to wet or dry surfaces, indoors and outdoors. Its tough and can handle up to 400% joint movement. Its scrubbable. It sticks to just about anything. Lexel clear caulk is 19 times clearer than silicone and won’t yellow or cloud up over time. Lexel won’t let you down.

Use on: tile, granite, glass, vinyl, wood, most metals and plastics, drywall and much more
Sticks to almost anything wet or dry even in extreme heat and freezing temperatures
Extreme elasticity - moves with materials due to shifting soils, temperatures and moisture so it won't crack over time
Won't grow mildew
Stretches up to 800%
Ultimate clarity - 19X clearer than silicone and won't yellow or get cloudy overtime
Paintable
Sticks to itself

I recommend to use gaskets to prevent dust and water leakage.

The potential of using them is if they became loose, then they may allow moisture penetration which lead to camera failure.

I've been advised to use self-fusing tape like this one around the opening of the cable whip/pigtail to add a bit more protection from the elements. It's worked fine as far as I know! I personally would rather use some sort of sealant, though - just because of flexibility of application. There's a high risk of not applying tape like this well. 

This is the sealant we like using too. It works well on just about anything, is clear and paintable. Also comes in small tubes, larger ones that require a gun and can be bought in bulk on Amazon. Ideally, however, you want it to have 24 hours without a lot of water exposure to cure. Haven't tested how it handles a downpour of rain shortly after being applied. 

Avigilon weatherproof camera enclosure.
This technically falls under methods of waterproofing.

Upsides:
Weatherproof.
Glass window offers excellent image quality
Includes cable managed bracket and sunshield
Compatible with optional PoE + power module.

Downsides:
Non applicable to a wide range of cameras and types of installs.
Kinda costly for smaller jobs.

This cable gland comes with FLIR FC cameras.  Advantages: free comes with camera,  has additional holes for power and a analog video cable,   covered under warranty by FLIR.  Disadvantage the plugs are easy to lose during installation. 

GE Supreme Silicone white 10 oz tube. 

Paint and or water ready in 10 min. Lifetime against shrinkage and cracking. Good for outdoor use and inexpensive about $9.00 for a 10oz tube,

Not water cleanup. 

3M 5200. Polyurethane sealer adhesive. Strong bond strength water proof can be applied to a wet surface without an adverse affect.  Can be submerged indefinitely. Can handle environments that most sealers are not able to. 

Not water clean up. Difficult to remove bonded parts. In most cases all but impossible to remove plastic parts without damage.  More expensive than other sealers $18 for a 10 oz tube. An excellent  product if needed but is over kill if not. 

We use the hand-squeeze tube of Lexel in various situations. Often, it is easy to get into tighter spaces as well as providing a little bit more accuracy with sealant placement. The downfall being that it is difficult to squeeze the last ounce or so out of the tube. 

I have never weather proofed a camera install, but I have weatherproofed many wireless AP antenna connections.  To do that I used a layer of electrical tape wrapped over the antenna connection, followed by a layer of Scotch 2228 Moisture sealing electrical tape, followed by another layer of electrical tape wrapped the other direction, followed by another layer of the Scotch 2228 tape followed by a final layer of electrical tape.  all seams and cuts were as smooth as possible to avoid any water build up. 

Downsides are if you wrap it poorly water will get in.  The tape is very sticky and it gets all over your hands so wearing gloves would be recommended. 

After reading a number of these posts, I would like to try the Lexel product everyone is raving about as it sounds like a really good option.  

I have used this tape to waterproof joint connections where I either had to couple a male whip connection to a network cable or I wanted to further protect a connection that didn't a screw type connector or something with a gasket or grommet.

After taking this class, though, I think I would use this as a last resort or as extra protection on a semi-sealed connection.

This sealant is waterproof, flexible, sticks to almost anything. Con is it is a little pricey at $13 a bottle.

Clear Window and Door Sealant, Silicone, 2.8 oz. Tube

I noticed Jeff uses the same silicone that I prefer to use when I have to water proof any type of outdoor box or camera. 

1. It comes out easy, the top doesn't get hard

2. If your finger is wet before using it, it won't stick to your hand

3. I like it because it's clear and you can put it on anything. It doesn't have to match the material. Looks cleaner.

3M Marine Adhesive Sealent

 Forms watertight, weather-resistant seal above and below the waterline which allow us to install and seal in the rain.

Adheres to Fiberglass,Metal,Plastic,Wood

This, like many other sealants is flexible and paintable

The downfall to this is it could take longer then 48 hours to dry